Inventive concepts relate to semiconductor memory devices, controllers, and semiconductor memory systems, and more particularly, to a semiconductor memory device, which interfaces between a memory controller and a memory that operates at high speed by using an optical link, a controller, and a semiconductor memory system.
Unlike an electric signal, an optical signal is sensitive to a mark ratio of 0 to 1. When a signal having a format not having a 1:1 mark ratio of 0 to 1 is transmitted, a receiver may not accurately process the signal.